‘Fat gene’ causes overeating in mice

A ‘fat gene' has been found to cause overeating in GM mice. The research may lead to an anti-obesity medicine that dampens appetite by reducing the activity of this gene.

Researchers bred mice with extra copies of the gene, called FTO, and observed their eating behaviour over 20 weeks. Mice with two extra copies of the gene were found to consume more food, causing female mice to become one fifth heavier and male mice to become a tenth heavier than normal. However, the effects on humans will not necessarily be so dramatic.

The FTO gene was first linked to obesity in 2007 when it was found that people with two copies of this genetic type (around one eighth of Europeans) were on average 3kg heavier than those without.

In order to develop an anti-obesity medicine, researchers say they must now understand exactly how the gene increases appetite. It is unclear whether the gene increases appetite by influencing our brain or by altering the messages to the body from fat stored in the body.

Almost 1 in 3 people in the UK are overweight or obese, predisposing them to diseases such as diabetes, heart disease and cancer. The estimated cost of obesity to the NHS is approximately £1 billion a year.